Acid Wash vs Jack's Magic for copper staining (suspected high CYA levels, what to look for to assess risk to plaster).

[QPSUtah]

Got called out to a customer's house where his plaster seems to have some pretty extensive copper staining (see pics). I went out for a different reason and didn't have the jack's magic stain kit, but there are blue stains across large swaths of his pool. I will confirm, but they appear to be copper.

He was requesting an acid wash but based on everything I've read here, I warned him it could disrupt the plaster finish. The pool was built about 30 years ago and replastered about 15 years ago. The plaster still felt pretty good to the touch on the steps and wall underneath the tile and otherwise looked good (but I am not yet a plaster expert).

He has also had the same water for 7-8 years, he indicated, and uses a tower/tab feeder, so I'm assuming his CYA levels are sky high (will also confirm on my next visit).

So a couple questions. If I were to use Jack's magic, the instructions indicate CYA levels must be below 70 for the identification and treatment to work. How critical is this for the identification part of the process? And the treatment part. I ask because ideally I would treat for the stain and then drain the pool to both bring CYA down as well as get the copper out of the pool. However, if we just drain once and then treat for the stain, I guess it would just the copper from the stain that remains in the pool... And maybe just maintain with blue stuff.

Given the plaster is 15 years old, would the plaster age be a pro or con for an acid wash? (I don't believe the re-plaster has been acid washed before).

What else should I look for in terms of inspecting the plaster to assess the risks of acid washing?

 

[ajw22]

So a couple questions. If I were to use Jack's magic, the instructions indicate CYA levels must be below 70 for the identification and treatment to work. How critical is this for the identification part of the process?

I would determine the CYA level and then call Jacks and discuss it with them.

And the treatment part. I ask because ideally I would treat for the stain and then drain the pool to both bring CYA down as well as get the copper out of the pool. However, if we just drain once and then treat for the stain, I guess it would just the copper from the stain that remains in the pool... And maybe just maintain with blue stuff.

Given the plaster is 15 years old, would the plaster age be a pro or con for an acid wash? (I don't believe the re-plaster has been acid washed before).

What else should I look for in terms of inspecting the plaster to assess the risks of acid washing?

What is your procedure for acid washing?

What dilution of acid to water do you use?

How long do you let the acid sit on the plaster walls or floor?

How and when do you neutralize the acidic solution?

Often, the acid wash reduces the life of plaster finishes, and no damage is visible immediately after the procedure.

Plaster finishes are damaged by people who don't know what they are doing and use too much acid for too long on the plaster. Do the people who will be doing it have experience? If so, they should be able to assess the plaster and know what they are doing. Otherwise, it can be a very expensive education for your crew.

 

[QPSUtah]

I would determine the CYA level and then call Jacks and discuss it with them.



What is your procedure for acid washing?

What dilution of acid to water do you use?

How long do you let the acid sit on the plaster walls or floor?

How and when do you neutralize the acidic solution?

Often, the acid wash reduces the life of plaster finishes, and no damage is visible immediately after the procedure.

Plaster finishes are damaged by people who don't know what they are doing and use too much acid for too long on the plaster. Do the people who will be doing it have experience? If so, they should be able to assess the plaster and know what they are doing. Otherwise, it can be a very expensive education for your crew.

I’ve got a couple techs who have done it before (I’m a new-ish owner and haven’t personally done it) but I’m not sure they’ve been trained to do it “the right way” in their previous employment or what to adjust depending on plaster condition etc.

 

[1poolman1]

Got called out to a customer's house where his plaster seems to have some pretty extensive copper staining (see pics). I went out for a different reason and didn't have the jack's magic stain kit, but there are blue stains across large swaths of his pool. I will confirm, but they appear to be copper.

He was requesting an acid wash but based on everything I've read here, I warned him it could disrupt the plaster finish. The pool was built about 30 years ago and replastered about 15 years ago. The plaster still felt pretty good to the touch on the steps and wall underneath the tile and otherwise looked good (but I am not yet a plaster expert).

He has also had the same water for 7-8 years, he indicated, and uses a tower/tab feeder, so I'm assuming his CYA levels are sky high (will also confirm on my next visit).

So a couple questions. If I were to use Jack's magic, the instructions indicate CYA levels must be below 70 for the identification and treatment to work. How critical is this for the identification part of the process? And the treatment part. I ask because ideally I would treat for the stain and then drain the pool to both bring CYA down as well as get the copper out of the pool. However, if we just drain once and then treat for the stain, I guess it would just the copper from the stain that remains in the pool... And maybe just maintain with blue stuff.

Given the plaster is 15 years old, would the plaster age be a pro or con for an acid wash? (I don't believe the re-plaster has been acid washed before).

What else should I look for in terms of inspecting the plaster to assess the risks of acid washing?

Don't acid wash that pool, the plaster will not survive. And you probably won't remove all the blue stain anyway. Its in bad shape now. If you look carefully at the stained areas you can see the aggregate that is in the plaster mix.
Most likely the re-plaster was a bond-coat then plaster job. That means that the new plaster would have been about 1/8" - 1/4" thick. Check just below the tile. Does there appear to be a slight angle to the plaster? Its less expensive that way, but 15 years is about the end of life for that job.
If you do decide to do the acid wash, be sure to get a signed waiver that explains what to expect. Most pool owners want a pool that is "new" again and that is not going to happen. I've done about 100 and you learn which to walk away from.

 

[JamesW]

You can try Jack’s #2 and then drain and refill if it is safe to drain without floating the pool out of the ground.

You can try a zero TA treatment, but that will eat some plaster and make the plaster rougher, but not as bad as an acid wash.

 

[JamesW]

An acid wash might help cosmetically, but it will seriously eat into the cement and leave the plaster very rough.

Below is a case where they acid washed and it looks a lot better, but they never reported on the plaster condition.

Two-Year-Old Pool Major Discoloration and Bleaching

Hi, Everyone! New to the forum and to pools in general. Closed on a house with my first pool! Yay! Although it's only two years old it has major discoloration (light and dark spots). General home inspector thought it was algae but the water is so clear. Here is what the prior owners...

www.troublefreepool.com

 

[JamesW]

Another option is to sand with a power sander and diamond grit pads.

I would probably do a Jack’s #2 followed by a drain and sand with fine grit diamond pads.

Note that draining always involves risk and you need to be sure that the pool will not float or have any other adverse effects.

 

[QPSUtah]

Don't acid wash that pool, the plaster will not survive. And you probably won't remove all the blue stain anyway. Its in bad shape now. If you look carefully at the stained areas you can see the aggregate that is in the plaster mix.
Most likely the re-plaster was a bond-coat then plaster job. That means that the new plaster would have been about 1/8" - 1/4" thick. Check just below the tile. Does there appear to be a slight angle to the plaster? Its less expensive that way, but 15 years is about the end of life for that job.
If you do decide to do the acid wash, be sure to get a signed waiver that explains what to expect. Most pool owners want a pool that is "new" again and that is not going to happen. I've done about 100 and you learn which to walk away from.

Yes. And came back out today to look more closely. As expected the CYA is too high to test without dilution. One drop seems to obscure the dot.

And I did notice that the “stains” do have the smooth finish worn away. So I’ll probably recommend replastering it and definitely not an acid wash. May still try the Jack’s magic treatment. I’ll confer with my local jack’s rep here to get his suggestion.

 

[QPSUtah]

Another option is to sand with a power sander and diamond grit pads.

I would probably do a Jack’s #2 followed by a drain and sand with fine grit diamond pads.

Note that draining always involves risk and you need to be sure that the pool will not float or have any other adverse effects.

The sanding would still shorten the plaster life, but obviously would make it smoother to walk on, so still just a temporary solution.

 

[JamesW]

The sanding would still shorten the plaster life

Not that much.

A better choice than replaster.

If you do a Jack's #2 first, that might do most of the work and the sanding can be very light with a finer grit sandpaper.

You can also take the TA down to zero after giving the Jack's #2 time to work.

Jack's #2 and zero TA can damage metals like the light and heater.

Take the system offline to do treatment.

Note: Draining involves risk and you need to make sure that it is safe to drain.